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<H1>IBM Visualization Data Explorer Programmer&#39;s Reference</H1>
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<H3><A NAME="HDRDXSOC" HREF="progu097.htm#PToC_413">DXSetOrthographic,
DXGetOrthographic</A></H3>
<A NAME="IDX2089"></A>
<A NAME="IDX2090"></A>
<A NAME="IDX2091"></A>
<A NAME="IDX2092"></A>
<P><STRONG>Function</STRONG>
<P>
Sets and retrieves an orthographic camera view.
<P><STRONG>Syntax</STRONG>
<BR>
<TT><STRONG><BR>
&#35;include &lt;dx/dx.h&gt;<BR>
<P><BR>
Camera DXSetOrthographic(Camera c, double width, double aspect)<BR>
Camera DXGetOrthographic(Camera c, double width, double aspect)<BR>
</STRONG></TT><BR>
<P><STRONG>Functional Details</STRONG>
<P>
A
camera defines the position and orientation of the viewer, the
volume of interest of the object being viewed, and the size of the
image to contain the resulting view.
<P>
<TT><STRONG>DXSetOrthographic</STRONG></TT> defines the volume of interest
for an orthographic camera
<TT><STRONG>c</STRONG></TT>.  This can be thought of as a box that is
centered on the <TT><STRONG>to</STRONG></TT> point, with its
<TT><STRONG>z</STRONG></TT> axis parallel to the
<TT><STRONG>to</STRONG></TT>-<TT><STRONG>from</STRONG></TT> vector, and infinite
in length.  Its <TT><STRONG>y</STRONG></TT> axis is perpendicular to the
<TT><STRONG>to</STRONG></TT>-<TT><STRONG>from</STRONG></TT> vector in the
direction
of the <TT><STRONG>up</STRONG></TT> vector.  Its <TT><STRONG>x</STRONG></TT>
axis is perpendicular to its
<TT><STRONG>y</STRONG></TT> and <TT><STRONG>z</STRONG></TT> axes.
The x and y dimensions of the box are given by the
<TT><STRONG>width</STRONG></TT> and
<TT><STRONG>aspect</STRONG></TT> parameters of the camera respectively,
where
<TT><STRONG>aspect</STRONG></TT> is defined as the ration of the height to
width.
<P>
In orthographic projection, objects do not appear smaller as they
get more distant, and in fact, distance between the object and
viewer have no effect on the appearance of the object.  The distance
between the
<TT><STRONG>to</STRONG></TT> and <TT><STRONG>from</STRONG></TT> points is
irrelevant; only the direction is important.
<P>
<TT><STRONG>DXGetOrthographic</STRONG></TT> returns the
<TT><STRONG>width</STRONG></TT> and <TT><STRONG>aspect</STRONG></TT> parameters
of an orthographic camera
<TT><STRONG>c</STRONG></TT>.  If width is not
<TT><STRONG>NULL</STRONG></TT>, the camera width is returned in
<TT><STRONG>*width</STRONG></TT>.  If aspect is not
<TT><STRONG>NULL</STRONG></TT>, the camera aspect is returned in
<TT><STRONG>*aspect</STRONG></TT>.
<P><STRONG>Return Value</STRONG>
<P>
<TT><STRONG>DXSetOrthographic</STRONG></TT> returns the camera or returns
<TT><STRONG>NULL</STRONG></TT> and sets an error code.
<P>
<TT><STRONG>DXGetOrthographic</STRONG></TT> returns the parameters or returns
<TT><STRONG>NULL</STRONG></TT> (if the camera is not orthographic) and
sets an error code (if <TT><STRONG>c</STRONG></TT> is not a
valid camera).
<P><STRONG>See Also</STRONG>
<P>
<TT><STRONG>
<A HREF="progu160.htm#HDRDXGCMP">DXGetCameraMatrix, DXGetCameraRotation,
DXGetCameraMatrixWithFuzz</A>,
<A HREF="progu246.htm#HDRDXNCA">DXNewCamera</A>,
<A HREF="progu292.htm#HDRDXRNDR">DXRender</A>,
<A HREF="progu323.htm#HDRDXSPE">DXSetPerspective, DXGetPerspective</A>,
<A HREF="progu324.htm#HDRDXSRN">DXSetResolution, DXGetCameraResolution</A>,
<A HREF="progu328.htm#HDRDXSVW">DXSetView, DXGetView</A>
</STRONG></TT>
<P>
<A HREF="progu081.htm#HDRCAMSEC">16.7 , "Camera Class"</A>.
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